A linear motor with a primary part and a secondary part which is capable of being displaced relative thereto is known from DE 42 17 357 A1. The primary part has coils which have a polyphase alternating current applied to them so as to induce the magnetic field extending along a movement axis of the secondary part. In this case, the primary part forms a stator and the secondary part forms a moveable rotor. Soft-magnetic teeth, which focus lines of force of the magnetic field and intensify the magnetic field induced by the coils, are arranged between the coils.
In the case of electric motors with a primary part inducing a magnetic field, it is known that the magnetizability of the stator material used is restricted by the material properties, i.e. the saturation magnetization. When using high current densities in the turns of the primary part, saturation occurs, i.e. a greater magnetomotive force cannot be achieved. The magnetic flux density is generally defined as the flux of the increased magnetic field through an area.
The generic U.S. Pat. No. 3,911,706 discloses a linear motor with a stator, which comprises soft-magnetic stator sleeves and stator annular disks alternately stacked one on top of the other. Coils are arranged between the stator annular disks. The stator sleeves, the stator annular disks and the coils are arranged concentrically with respect to a receptacle for a rotor. In an embodiment disclosed in U.S. Pat. No. 3,911,706, tooth tip pieces made from a material with a relatively high magnetizability and in the form of a T in cross section are arranged on the inner circumference of the stator annular disks, directly adjacent to the receptacle. In each case insulating or reinforcing rings are arranged between the sections of the T-shaped tooth tip pieces which protrude laterally over the stator annular disks, and the coils extend in the radial direction as far as the tooth tip pieces or the insulating rings which protrude laterally over the stator annular disks.
DE 2 336 893 discloses a primary part comprising an iron core with iron laminates as teeth. The teeth are separated from one another by means of slots, which are wider at a distance from the tooth tips than in the region of the tooth tips. Windings or coils are accommodated in the wider slot sections further removed from the receptacle, while the narrower slots arranged closer to the receptacle are filled by means of filling elements for reinforcing the primary part. All of the remaining regions after the introduction of the filling elements are cast with a pourable filling compound which is borne by the filling elements.
The linear motors which are available at present on the market can be used as actuating and positioning elements and in this case achieve surface force densities of up to 8 N/cm2.